1 files changed, 436 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
new file mode 100644
index 000000000..3cd1ef563
--- /dev/null
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -0,0 +1,436 @@
+//! The AOT driver uses [`cranelift_object`] to write object files suitable for linking into a
+//! standalone executable.
+
+use std::path::PathBuf;
+
+use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
+use rustc_codegen_ssa::back::metadata::create_compressed_metadata_file;
+use rustc_codegen_ssa::{CodegenResults, CompiledModule, CrateInfo, ModuleKind};
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_metadata::EncodedMetadata;
+use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
+use rustc_middle::mir::mono::{CodegenUnit, MonoItem};
+use rustc_session::cgu_reuse_tracker::CguReuse;
+use rustc_session::config::{DebugInfo, OutputType};
+use rustc_session::Session;
+
+use cranelift_codegen::isa::TargetIsa;
+use cranelift_object::{ObjectBuilder, ObjectModule};
+
+use crate::{prelude::*, BackendConfig};
+
+struct ModuleCodegenResult(CompiledModule, Option<(WorkProductId, WorkProduct)>);
+
+impl<HCX> HashStable<HCX> for ModuleCodegenResult {
+    fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) {
+        // do nothing
+    }
+}
+
+fn make_module(sess: &Session, isa: Box<dyn TargetIsa>, name: String) -> ObjectModule {
+    let mut builder =
+        ObjectBuilder::new(isa, name + ".o", cranelift_module::default_libcall_names()).unwrap();
+    // Unlike cg_llvm, cg_clif defaults to disabling -Zfunction-sections. For cg_llvm binary size
+    // is important, while cg_clif cares more about compilation times. Enabling -Zfunction-sections
+    // can easily double the amount of time necessary to perform linking.
+    builder.per_function_section(sess.opts.unstable_opts.function_sections.unwrap_or(false));
+    ObjectModule::new(builder)
+}
+
+fn emit_module(
+    tcx: TyCtxt<'_>,
+    backend_config: &BackendConfig,
+    name: String,
+    kind: ModuleKind,
+    module: ObjectModule,
+    debug: Option<DebugContext<'_>>,
+    unwind_context: UnwindContext,
+) -> ModuleCodegenResult {
+    let mut product = module.finish();
+
+    if let Some(mut debug) = debug {
+        debug.emit(&mut product);
+    }
+
+    unwind_context.emit(&mut product);
+
+    let tmp_file = tcx.output_filenames(()).temp_path(OutputType::Object, Some(&name));
+    let obj = product.object.write().unwrap();
+
+    tcx.sess.prof.artifact_size("object_file", name.clone(), obj.len().try_into().unwrap());
+
+    if let Err(err) = std::fs::write(&tmp_file, obj) {
+        tcx.sess.fatal(&format!("error writing object file: {}", err));
+    }
+
+    let work_product = if backend_config.disable_incr_cache {
+        None
+    } else {
+        rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
+            tcx.sess,
+            &name,
+            &[("o", &tmp_file)],
+        )
+    };
+
+    ModuleCodegenResult(
+        CompiledModule { name, kind, object: Some(tmp_file), dwarf_object: None, bytecode: None },
+        work_product,
+    )
+}
+
+fn reuse_workproduct_for_cgu(
+    tcx: TyCtxt<'_>,
+    cgu: &CodegenUnit<'_>,
+    work_products: &mut FxHashMap<WorkProductId, WorkProduct>,
+) -> CompiledModule {
+    let work_product = cgu.previous_work_product(tcx);
+    let obj_out = tcx.output_filenames(()).temp_path(OutputType::Object, Some(cgu.name().as_str()));
+    let source_file = rustc_incremental::in_incr_comp_dir_sess(
+        &tcx.sess,
+        &work_product.saved_files.get("o").expect("no saved object file in work product"),
+    );
+    if let Err(err) = rustc_fs_util::link_or_copy(&source_file, &obj_out) {
+        tcx.sess.err(&format!(
+            "unable to copy {} to {}: {}",
+            source_file.display(),
+            obj_out.display(),
+            err
+        ));
+    }
+
+    work_products.insert(cgu.work_product_id(), work_product);
+
+    CompiledModule {
+        name: cgu.name().to_string(),
+        kind: ModuleKind::Regular,
+        object: Some(obj_out),
+        dwarf_object: None,
+        bytecode: None,
+    }
+}
+
+fn module_codegen(
+    tcx: TyCtxt<'_>,
+    (backend_config, cgu_name): (BackendConfig, rustc_span::Symbol),
+) -> ModuleCodegenResult {
+    let cgu = tcx.codegen_unit(cgu_name);
+    let mono_items = cgu.items_in_deterministic_order(tcx);
+
+    let isa = crate::build_isa(tcx.sess, &backend_config);
+    let mut module = make_module(tcx.sess, isa, cgu_name.as_str().to_string());
+
+    let mut cx = crate::CodegenCx::new(
+        tcx,
+        backend_config.clone(),
+        module.isa(),
+        tcx.sess.opts.debuginfo != DebugInfo::None,
+        cgu_name,
+    );
+    super::predefine_mono_items(tcx, &mut module, &mono_items);
+    for (mono_item, _) in mono_items {
+        match mono_item {
+            MonoItem::Fn(inst) => {
+                cx.tcx
+                    .sess
+                    .time("codegen fn", || crate::base::codegen_fn(&mut cx, &mut module, inst));
+            }
+            MonoItem::Static(def_id) => crate::constant::codegen_static(tcx, &mut module, def_id),
+            MonoItem::GlobalAsm(item_id) => {
+                let item = cx.tcx.hir().item(item_id);
+                if let rustc_hir::ItemKind::GlobalAsm(asm) = item.kind {
+                    if !asm.options.contains(InlineAsmOptions::ATT_SYNTAX) {
+                        cx.global_asm.push_str("\n.intel_syntax noprefix\n");
+                    } else {
+                        cx.global_asm.push_str("\n.att_syntax\n");
+                    }
+                    for piece in asm.template {
+                        match *piece {
+                            InlineAsmTemplatePiece::String(ref s) => cx.global_asm.push_str(s),
+                            InlineAsmTemplatePiece::Placeholder { .. } => todo!(),
+                        }
+                    }
+                    cx.global_asm.push_str("\n.att_syntax\n\n");
+                } else {
+                    bug!("Expected GlobalAsm found {:?}", item);
+                }
+            }
+        }
+    }
+    crate::main_shim::maybe_create_entry_wrapper(
+        tcx,
+        &mut module,
+        &mut cx.unwind_context,
+        false,
+        cgu.is_primary(),
+    );
+
+    let debug_context = cx.debug_context;
+    let unwind_context = cx.unwind_context;
+    let codegen_result = tcx.sess.time("write object file", || {
+        emit_module(
+            tcx,
+            &backend_config,
+            cgu.name().as_str().to_string(),
+            ModuleKind::Regular,
+            module,
+            debug_context,
+            unwind_context,
+        )
+    });
+
+    codegen_global_asm(tcx, cgu.name().as_str(), &cx.global_asm);
+
+    codegen_result
+}
+
+pub(crate) fn run_aot(
+    tcx: TyCtxt<'_>,
+    backend_config: BackendConfig,
+    metadata: EncodedMetadata,
+    need_metadata_module: bool,
+) -> Box<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>)> {
+    let mut work_products = FxHashMap::default();
+
+    let cgus = if tcx.sess.opts.output_types.should_codegen() {
+        tcx.collect_and_partition_mono_items(()).1
+    } else {
+        // If only `--emit metadata` is used, we shouldn't perform any codegen.
+        // Also `tcx.collect_and_partition_mono_items` may panic in that case.
+        &[]
+    };
+
+    if tcx.dep_graph.is_fully_enabled() {
+        for cgu in &*cgus {
+            tcx.ensure().codegen_unit(cgu.name());
+        }
+    }
+
+    let modules = super::time(tcx, backend_config.display_cg_time, "codegen mono items", || {
+        cgus.iter()
+            .map(|cgu| {
+                let cgu_reuse = determine_cgu_reuse(tcx, cgu);
+                tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);
+
+                match cgu_reuse {
+                    _ if backend_config.disable_incr_cache => {}
+                    CguReuse::No => {}
+                    CguReuse::PreLto => {
+                        return reuse_workproduct_for_cgu(tcx, &*cgu, &mut work_products);
+                    }
+                    CguReuse::PostLto => unreachable!(),
+                }
+
+                let dep_node = cgu.codegen_dep_node(tcx);
+                let (ModuleCodegenResult(module, work_product), _) = tcx.dep_graph.with_task(
+                    dep_node,
+                    tcx,
+                    (backend_config.clone(), cgu.name()),
+                    module_codegen,
+                    Some(rustc_middle::dep_graph::hash_result),
+                );
+
+                if let Some((id, product)) = work_product {
+                    work_products.insert(id, product);
+                }
+
+                module
+            })
+            .collect::<Vec<_>>()
+    });
+
+    tcx.sess.abort_if_errors();
+
+    let isa = crate::build_isa(tcx.sess, &backend_config);
+    let mut allocator_module = make_module(tcx.sess, isa, "allocator_shim".to_string());
+    assert_eq!(pointer_ty(tcx), allocator_module.target_config().pointer_type());
+    let mut allocator_unwind_context = UnwindContext::new(allocator_module.isa(), true);
+    let created_alloc_shim =
+        crate::allocator::codegen(tcx, &mut allocator_module, &mut allocator_unwind_context);
+
+    let allocator_module = if created_alloc_shim {
+        let ModuleCodegenResult(module, work_product) = emit_module(
+            tcx,
+            &backend_config,
+            "allocator_shim".to_string(),
+            ModuleKind::Allocator,
+            allocator_module,
+            None,
+            allocator_unwind_context,
+        );
+        if let Some((id, product)) = work_product {
+            work_products.insert(id, product);
+        }
+        Some(module)
+    } else {
+        None
+    };
+
+    let metadata_module = if need_metadata_module {
+        let _timer = tcx.prof.generic_activity("codegen crate metadata");
+        let (metadata_cgu_name, tmp_file) = tcx.sess.time("write compressed metadata", || {
+            use rustc_middle::mir::mono::CodegenUnitNameBuilder;
+
+            let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
+            let metadata_cgu_name = cgu_name_builder
+                .build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata"))
+                .as_str()
+                .to_string();
+
+            let tmp_file =
+                tcx.output_filenames(()).temp_path(OutputType::Metadata, Some(&metadata_cgu_name));
+
+            let symbol_name = rustc_middle::middle::exported_symbols::metadata_symbol_name(tcx);
+            let obj = create_compressed_metadata_file(tcx.sess, &metadata, &symbol_name);
+
+            if let Err(err) = std::fs::write(&tmp_file, obj) {
+                tcx.sess.fatal(&format!("error writing metadata object file: {}", err));
+            }
+
+            (metadata_cgu_name, tmp_file)
+        });
+
+        Some(CompiledModule {
+            name: metadata_cgu_name,
+            kind: ModuleKind::Metadata,
+            object: Some(tmp_file),
+            dwarf_object: None,
+            bytecode: None,
+        })
+    } else {
+        None
+    };
+
+    // FIXME handle `-Ctarget-cpu=native`
+    let target_cpu = match tcx.sess.opts.cg.target_cpu {
+        Some(ref name) => name,
+        None => tcx.sess.target.cpu.as_ref(),
+    }
+    .to_owned();
+
+    Box::new((
+        CodegenResults {
+            modules,
+            allocator_module,
+            metadata_module,
+            metadata,
+            crate_info: CrateInfo::new(tcx, target_cpu),
+        },
+        work_products,
+    ))
+}
+
+fn codegen_global_asm(tcx: TyCtxt<'_>, cgu_name: &str, global_asm: &str) {
+    use std::io::Write;
+    use std::process::{Command, Stdio};
+
+    if global_asm.is_empty() {
+        return;
+    }
+
+    if cfg!(not(feature = "inline_asm"))
+        || tcx.sess.target.is_like_osx
+        || tcx.sess.target.is_like_windows
+    {
+        if global_asm.contains("__rust_probestack") {
+            return;
+        }
+
+        // FIXME fix linker error on macOS
+        if cfg!(not(feature = "inline_asm")) {
+            tcx.sess.fatal(
+                "asm! and global_asm! support is disabled while compiling rustc_codegen_cranelift",
+            );
+        } else {
+            tcx.sess.fatal("asm! and global_asm! are not yet supported on macOS and Windows");
+        }
+    }
+
+    let assembler = crate::toolchain::get_toolchain_binary(tcx.sess, "as");
+    let linker = crate::toolchain::get_toolchain_binary(tcx.sess, "ld");
+
+    // Remove all LLVM style comments
+    let global_asm = global_asm
+        .lines()
+        .map(|line| if let Some(index) = line.find("//") { &line[0..index] } else { line })
+        .collect::<Vec<_>>()
+        .join("\n");
+
+    let output_object_file = tcx.output_filenames(()).temp_path(OutputType::Object, Some(cgu_name));
+
+    // Assemble `global_asm`
+    let global_asm_object_file = add_file_stem_postfix(output_object_file.clone(), ".asm");
+    let mut child = Command::new(assembler)
+        .arg("-o")
+        .arg(&global_asm_object_file)
+        .stdin(Stdio::piped())
+        .spawn()
+        .expect("Failed to spawn `as`.");
+    child.stdin.take().unwrap().write_all(global_asm.as_bytes()).unwrap();
+    let status = child.wait().expect("Failed to wait for `as`.");
+    if !status.success() {
+        tcx.sess.fatal(&format!("Failed to assemble `{}`", global_asm));
+    }
+
+    // Link the global asm and main object file together
+    let main_object_file = add_file_stem_postfix(output_object_file.clone(), ".main");
+    std::fs::rename(&output_object_file, &main_object_file).unwrap();
+    let status = Command::new(linker)
+        .arg("-r") // Create a new object file
+        .arg("-o")
+        .arg(output_object_file)
+        .arg(&main_object_file)
+        .arg(&global_asm_object_file)
+        .status()
+        .unwrap();
+    if !status.success() {
+        tcx.sess.fatal(&format!(
+            "Failed to link `{}` and `{}` together",
+            main_object_file.display(),
+            global_asm_object_file.display(),
+        ));
+    }
+
+    std::fs::remove_file(global_asm_object_file).unwrap();
+    std::fs::remove_file(main_object_file).unwrap();
+}
+
+fn add_file_stem_postfix(mut path: PathBuf, postfix: &str) -> PathBuf {
+    let mut new_filename = path.file_stem().unwrap().to_owned();
+    new_filename.push(postfix);
+    if let Some(extension) = path.extension() {
+        new_filename.push(".");
+        new_filename.push(extension);
+    }
+    path.set_file_name(new_filename);
+    path
+}
+
+// Adapted from https://github.com/rust-lang/rust/blob/303d8aff6092709edd4dbd35b1c88e9aa40bf6d8/src/librustc_codegen_ssa/base.rs#L922-L953
+fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
+    if !tcx.dep_graph.is_fully_enabled() {
+        return CguReuse::No;
+    }
+
+    let work_product_id = &cgu.work_product_id();
+    if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
+        // We don't have anything cached for this CGU. This can happen
+        // if the CGU did not exist in the previous session.
+        return CguReuse::No;
+    }
+
+    // Try to mark the CGU as green. If it we can do so, it means that nothing
+    // affecting the LLVM module has changed and we can re-use a cached version.
+    // If we compile with any kind of LTO, this means we can re-use the bitcode
+    // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
+    // know that later). If we are not doing LTO, there is only one optimized
+    // version of each module, so we re-use that.
+    let dep_node = cgu.codegen_dep_node(tcx);
+    assert!(
+        !tcx.dep_graph.dep_node_exists(&dep_node),
+        "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
+        cgu.name()
+    );
+
+    if tcx.try_mark_green(&dep_node) { CguReuse::PreLto } else { CguReuse::No }
+}